As a part-time tennis pro. The combined benefits of watching the best in the world and then comparing it to a video of yourself playing is tremendous for most people.

And for tennis in particular, the court level angle especially shows just how good these players are. There was an Isner vs. Djokovic court level video that's now taken down (the full quality version), and seeing up close the speed at which Djokovic would change directions and return one of the biggest serves was astounding.